Considerable attention in recent years has been directed to the intravenous delivery of fluids such as saline solutions and the like to patients. Initially, these fluids were administered to the patient by means of gravity flow from a container holding the fluid to be delivered. Gravity-flow devices, however, proved cumbersome to use, inasmuch as pressure sufficient to sustain fluid movement in a gravity-flow device often required positioning of the device at a considerable elevation above the patient receiving the fluid. Moreover, attempts to accurately regulate the amount of fluid administered by gravity-flow devices were often unsuccessful because of the fact that the gravity-induced pressure responsible for moving fluid through the device generally decreased as the fluid level within the container holding the fluid dropped during the intravenous delivery operation.